Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacterial DNA reduces inflammation in mice

03.02.2004


DNA from inactivated "probiotic" bacteria triggers a specific anti-inflammation immune response in mice with experimental colitis, researchers supported by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID) have discovered. Led by Eyal Raz, M.D., of the University of California, San Diego (UCSD), the investigators provide a possible explanation for the observed benefits of consuming probiotics, supplements from bacteria and other microbes, regarded by some as helpful in maintaining or restoring intestinal health. Knowing how probiotics work could give scientists a way to identify and select which probiotic bacteria might be effective against such human ailments as inflammatory bowel disease (IBD).



Probiotics have shown promise for treating such IBDs as Crohn’s disease and ulcerative colitis, both of which cause periodic intestinal inflammation. But scientists have had many theories of how these mixtures of "good" bacteria work, notes Marshall Plaut, M.D., of NIAID’s Division of Allergy, Immunology and Transplantation. Plausible theories suggested that proliferation of the living bacteria either generated helpful metabolic products or crowded out "bad" intestinal bugs. Prior to this study, the general thinking about probiotics, which include bacteria like those found in yogurt, has been that they mediate their effects through some kind of non-specific action, adds Dr. Plaut.

Dr. Raz and his colleagues, whose work is published in the February 2004 issue of the journal Gastroenterology, irradiated a commercially available probiotic preparation, halting bacterial proliferation, but preserving its DNA. When given to mice, the irradiated probiotics performed as well as live bacteria in reducing inflammation. They also found that purified probiotic bacterial DNA alone similarly reduces inflammation in mice with experimentally induced colitis.


The researchers also showed that probiotic DNA acts in a specific way by activating a defined element within the innate immune system. In animals, including humans, components of the innate immune system play complementary roles in initiating, then halting, inflammation. Improperly regulated inflammation is one symptom of IBDs.

An innate immune system protein called TLR9 is a pivotal player in the chemical signaling chain that slows inflammation. In a series of experiments, the UCSD team showed that probiotic DNA exerts its effects through TLR9. Indeed, mice without the gene for TLR9 protein cannot benefit from probiotics, either living or irradiated, or from probiotic DNA.

Taken together, insights into mechanisms of probiotic activity open new possibilities for probiotic therapies. For example, say some researchers, purified probiotic DNA or irradiated probiotics may be safer than viable preparations, and could be used by people with compromised immune systems.

Dr. Raz also received support for this research from the National Institute of Diabetes and Digestive and Kidney Diseases, a part of the NIH.


NIAID is a component of the National Institutes of Health (NIH), which is an agency of the Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

Reference: D Rachmilewitz et al. Toll-like receptor 9 signaling mediates the anti-inflammatory effects of probiotics in murine experimental colitis. Gastroenterology. (Feb. 2004) DOI:10.1053/j.gastro.2003.11.019.

Anne A. Oplinger | EurekAlert!
Further information:
http://://www.niaid.nih.gov/

More articles from Health and Medicine:

nachricht Nitric oxide-scavenging hydrogel developed for rheumatoid arthritis treatment
06.06.2019 | Pohang University of Science & Technology (POSTECH)

nachricht Infants later diagnosed with autism follow adults’ gaze, but seldom initiate joint attention
24.05.2019 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Uncovering hidden protein structures

18.06.2019 | Life Sciences

Monitoring biodiversity with sound: how machines can enrich our knowledge

18.06.2019 | Life Sciences

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>